Method of constructing submersible structures utilizing submarine hulls

ABSTRACT

Submersible offshore drilling rig or other type of submersible marine vessel having submarine hulls as its base and a method of construction thereof is disclosed. The structure disclosed is comprised of a drilling rig, for example, mounted on a platform having its lower leg members attached to a multiplicity of submarine hulls. The structure illustrated is designed to be used in the drilling of offshore oil and gas wells, but the invention is not limited thereto. The structure is constructed such that the drilling rig or other marine vessel is mounted onto a multiplicity of legs which are in turn connected to pontoons. The pontoons in the instant device consists of standard, surplus submarine hulls which have been modified for use in connection with drilling rig structures. The submarine hulls usually are equipped with ballast controls, self propulsion means, electric generators, air compressors, fresh water stills and other builtin features which can be all used in connection with the marine drilling rig.

United States Patent Sanders Apr. 1, 1975 METHOD OF CONSTRUCTING SUBMERSIBLE STRUCTURES UTILIZING [57] ABSTRACT SUBMARINE HULLS S b bl ff h d n h t f b u mersi e o s ore II mg mg or ot er ype o su [76] inventor 'L g gaggg Winsome mersible marine vessel having submarine hulls as its ous base and a method of construction thereof is dis- [22] Filed: June 29, 1973 closed. The structure disclosed is comprised of a dril- I ling rig, for example, mountedl on a platform having its [21] Appl' 375018 lower leg members attached to a multiplicity of submarine hulls. The structure illustrated is designed to [52] U.S. Cl. 114/.5 D, l 14/61 be used in the drilling of offshore oil and gas wells, but [51] Int. Cl B63b 35/44 the invention is not limited thereto. The structure is [58] Field of Search 114/.5 D, .5 R, 43.5, 61, constructed such that the drilling rig or other marine l 14/66.5 R, 66.5 H vessel is mounted onto a multiplicity of legs which are in turn connected to pontoons. The pontoons in the [56] References Cited instant device consists of standard, surplus submarine UNITED STATES PATENTS hulls which have been modified for use in connection with drilling rig structures. The submarine hulls usuga i ally are equipped with ballast controls, self propulsion 3:623:444 11/1971 Lang ..LIL.......III: i iZ/.5 D ux meme electric generators, air Compressors, fresh water stills and other builtin features which can be all n Blix used in connection with the marine drilling rig. Assistant Examiner-Stuart M. Goldstein Attorney. Agent, or Firm-Pugh & Laiche 6 Claims 5 Drawing Figures PATENTED APR 1 I95 snwau q ATENTED APR 3 W5 lllllllllllllllll' llllllllllHH I IIIIIIIIIIHIIHI' FIG. 3

METHOD OF CONSTRUCTING SUBMERSIBLE STRUCTURES UTILIZING SUBMARINE HULLS BACKGROUND OF THE PRESENT INVENTION In the recent past, there has been agrowing propensity for the United States to rely on foreign produced oil to meet its domestic needs. This, coupled with inflation, has caused an enormous balance of payments problems which in turn weakens the dollar abroad. As a result of this situation, there has developed an energy crisis which in and of itself points to the need for additional emphasis in the economical provision of oil and gas. t

In addition to the foregoing problems, there is a shortage in the supply of domestic steel such as the type used to fabricate an offshore drilling rig apparatus. As a partial solution to the problem of limited supplies of steel, manufacturers have resorted to reusing obsolescent or junk steel products. Usually this requires that the steel be recycled thereby adding to its costs in manufacturing new products.

It is an object of the present invention to provide a relatively inexpensive submersible structure such as for example an offshore drilling rig. The cost for manufacturing the instant device is greatly reduced due to the substantial reduction in manhours necessary in its manufacture as well as a reduction in the costs of the steel structure used in connection therewith. Indeed it is estimated that approximately ten million dollars can be saved in the cost of a drilling rig such as that disclosed by the use of the present invention. This tremendous savings is accomplished by utilizing surplus, demilitarized submarines as the lower hulls of semi-submersible or submersible equipment for use for example in offshore mineral oil and gas exploration as well as other uses in the marine area. In the preferred embodiment, a conventional offshore drilling rig with attached legs is attached to the modified hulls of abandoned or surplus submarines in place of the standard pontoons.

Among the advantages of the present invention are lower cost of construction, lowering of the center of gravity thereby making the marine structure more stable thus more workable in rough seas and weather and making good use of steel and existing equipment already assembled. connected, and in place, which would otherwise be destroyed as scrap. Obviously, greater income to the government would be generated by using surplus submarines to a more useful purpose in its present state, rather than reducing valuable equipment to its basic state as scrap.

DESCRIPTION OF THE DRAWINGS Other and more particular advantages will become apparent from the following drawings in which like references refer to like parts thereof throughout the various views and diagrams and in which:

FIG. 1 is a perspective view of the entire offshore drilling rig which serves as an exemplary embodiment of the present invention;

FIG. 2 is a top perspective view of the legs and the submarine" pontoons of the offshore drilling rig of FIG. 1;

FIG. 3 is a side perspective view of the submarine pontoons and legs of the offshore drilling rig; and

FIG. 4 is a front perspective view of the legs and submarine pontoons of the offshore drilling rig.

FIG. 5 is a side view of a typical submarine which can be used in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, there is shown a submersible or semi-submersible offshore drilling rig 20 which is comprised of a deck 13, the dereck l4, legs 15 and intermediate legs 12, both of which act to support and connect the drilling structure to the submersible submarine pontoons l0. Submersible as-used herein includes both submersible and semi-submersible rig structures, the former usually referring to rigs which are floated to the job site but these are partially sunk so that the pontoons or hulls 10 rest in the bottom of the ocean, while the latter maintains its floating condition in use. I

I-Ieretofore, pontoons were constructed of conventional steel fabrication and equipped with necessary ballast controls, etc. The device and method disclosed herein utilizes surplus submarine hulls whose decks have been cleared of towers, masts and other paraphernalia so as to make the decks clear of unnecessary projections, thereby rendering them attachable to the legs 12 and 15.

Within the submarine hulls 10 are motors, engines, and generators which are to be utilized in their existing positions, thereby rendering the center of gravity lower and making the offshore rig 20 more stable. Also if additional stability is desired the standard submarine diving fins can be fixed in a horizontal position.

The rig 20 can use the submarine ballast control system of blowing tanks ratherthan pumping action which is the conventional way to remove water from standard pontoons as was previously used in conventional offshore drilling rig structures. Due to military necessity, the submarine hulls 10 have a ballast pumping system which is considerably more efficient than those currently used in industrial offshore dirlling rigs to-date. Remote controls located on upper deck 13 can be used to actuate and control the submarine ballast systems.

The various submarine inner-hull compartments can be converted into bulk mud and cement storage tanks and would double as a ballast and storage tank area. Passage compartments within legs 12 are provided as entrance means into submarine hulls 10. This is provided by cutting holes in the top of the submarine to accept shaft members within legs 12 for ingress and egress into submarine hulls l0.

Submarine hulls 10 are greater in size and weight than the conventional pontoons now being used and therefore enable the offshore drilling rig 20 to enjoy a greater degree of stability as well as allowing the upper structure of the rig to be constructed of lighter weight material. In addition, the submarines already being in the water permit construction to begin without the launching facility which is required in the launching of conventionally built rigs for use in offshore drilling rigs. Savings in launching is obtained by not requiring prime shipyards since a repair and conversion yard may be used requiring less skilled labor. The effect is that there is no necessity to obtain expensive competitive bidding since secondary yards are used.

FIG. 5 shows a typical submarine hull 51 with its diving fins 50 which can be used in the present invention. These fins have an inherent characteristic of stabilizing the submarine hull 51 which in turn can be used to stabilize any marine vessel attached to the hull 51. Submarines, such as the typical example illustrated in H6. 5, are well known in the marine art and are independent, self contained naval vessels. Such vessels, as illustrated in FIG. 5, usually have major external projections extending upward from its top deck, such as for example, a conning tower, and working implements such as cranes. or gun emplacements (not illustrated, but well known). For amore detailed. description of such vessels,'reference is made to, for example, the Encyclvpaedia Briranica,' 1972edition, Volume 21, page 335 et What is claimed is:

l. A' method for constructing a submersible structure, such as for example a submersible offshore drilling rig, having support legs and bottom pontoons comprising the following steps:

a. securing a set of standard surplus submarines which thereto fore had utility as separate, selfcontained marine vessels;

b. stripping the submarine hulls above their top deck ,of major external projections such as for example v y the conning tower and working implements; and

c. fixedly attaching the support legs of the submersible structure to the upper surface of said submarine hulls and utilizing said submarine hulls as the pontoons for the submersible structure.

2. The method defined in claim 1 wherein:

the motors, engines, and generators are retained in said submarine hulls and are used in the completed submersible structure.

3. The method defined in claim 1 wherein:

the diving fms connected to said submarine hulls are retained and locked in horizontal position, thereby adding to the stability of the submersible structure.

4. The method defined in claim 1 wherein:

the self-contained ballast control system within said submarine hulls are retained and are used for raising and lowering the submersible structure.

5. The method defined in claim 1 wherein:

said submarine hulls as the pontoons of the subme rsible structure are provided with openings positioned within the periphery of said legs for exit and entrance of personnel thereto.

6. The method defined in claim 1 wherein:

said submarine hulls as the pontoons of the submersible structure are used for housing mud and cement therein.

* as a 

1. A method for constructing a submersible structure, such as for example a submersible offshore drilling rig, having support legs and bottom pontoons comprising the following steps: a. securing a set of standard surplus submarines which theretofore had utility as separate, self-contained marine vessels; b. stripping the submarine hulls above their top deck of major external projections such as for example the conning tower and working implements; and c. fixedly attaching the support legs of the submersible structure to the upper surface of said submarine hulls and utilizing said submarine hulls as the pontoons for the submersible structure.
 2. The method defined in claim 1 wherein: the motors, engines, and generators are retained in said submarine hulls and are used in the completed submersible structure.
 3. The method defined in claim 1 wherein: the diving fins connected to said submarine hulls are retained and locked in horizontal position, thereby adding to the stability of the submersible structure.
 4. The method defined in claim 1 wherein: the self-contained ballast control system within said submarine hulls are retained and are used for raising and lowering the submersible structure.
 5. The method defined in claim 1 wherein: said submarine hulls as the pontoons of the submersible structure are provided with openings positioned within the periphery of said legs for exit and entrance of personnel thereto.
 6. The method defined in claim 1 wherein: said submarine hulls as the pontoons of the submersible structure are used for housing mud and cement therein. 